cron.8

Unix操作系统minix 2.0源码

CRON(8)                   Minix Programmer's Manual                    CRON(8)


NAME
     cron - clock daemon

SYNOPSIS
     cron

EXAMPLES

     /usr/bin/cron       # Use absolute path in /etc/rc

DESCRIPTION

     Cron is clock daemon.  It  is  typically  started  up  by  including  the
     command /usr/bin/cron in the /etc/rc file. Once started, cron puts itself
     in the background, so no & is needed.  It runs forever, sleeping most  of
     the time.  Once a minute it wakes up and examines /usr/lib/crontab to see
     if there is any work to do.  If there is, the work is done.  The  entries
     of /usr/lib/crontab contain 6 elements each.  Some examples follow:

      Min Hr Dat Mo Day   Command
       *  *   *   *  *    /usr/bin/date >/dev/log   #print date every minute
       0  *   *   *  *    /usr/bin/date >/dev/log   #print date on the hour
      30  4   *   * 1-5   /bin/backup /dev/fd1      #do backup Mon-Fri at 0430
      30 19   *   * 1,3,5 /etc/backup /dev/fd1      #Mon, Wed, Fri at 1930
       0  9  25  12  *    /usr/bin/sing >/dev/log   #Xmas morning at 0900 only

SEE ALSO
     at(1).
























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